1. Field of the Invention
The present disclosure generally relates to image forming and, more particularly, to an image forming apparatus which forms an image on a sheet.
2. Description of the Related Art
Conventionally, there has been provided an image forming apparatus exemplified by a multifunction printer (hereinafter referred to as an MFP) that includes a scanning function for reading an image from a document and a printing function for printing a scanned image on a sheet. A lamp lighting error and a motor error are examples of the failure states for the scanning function of the MFP. Further, abnormality in a fixing unit and abnormality in an intermediate transfer member are examples of the failure states for the printing function thereof.
In a case where the above failure has occurred in the conventional MFP, the MFP sends an error code (E-code) corresponding to that failure to an external computer in a remote place, so as to inform a service office of that external computer in the remote place that repair work performed by a service engineer may be necessary.
In such a case, the functions of the conventional MFP is suspended entirely even if the E-code is generated for the failure that has occurred in a part of the functions such as a scanning function. Therefore, even a job such as a function for selecting and printing a scanned image previously stored in a hard disk of the MFP, which does not use the scanning function, cannot be executed. Further, a function for simply printing the print data transmitted from the external computer to the MFP cannot be executed as well.
Accordingly, when the failure has occurred in the scanning function of the MFP, even if the service office in the remote place has been informed of the occurrence of the failure, the MFP will have a downtime. During the downtime, the printing operation cannot be executed until the service engineer visits the installation site of the MFP to complete the repair work.
In order to solve the above problems, Japanese Patent Application Laid-Open No. 2002-254781 discusses a technique which restricts a function having an abnormality while enabling the rest of functions even if the abnormality has occurred in a part of the functions.
Conventionally, the MFP has been provided with a power saving mode (sleep mode) function. In recent years, because there has been an increased demand in the MFP with an improved power saving mode function, there has been realized an excellent power-saving effect by promptly shifting to the sleep mode when the MFP is not in use.
Consequently, there is also a need to realize a function for shifting to the sleep mode from a function restriction state in case of the abnormality. Furthermore, in the recent sleep mode, there has been realized the power saving performance approximately the same as that in the power off period by shutting off the power supply to the unnecessary portions.
However, because the operation for returning from the sleep mode is regarded as the same as the normal power on operation, a preparation operation for the MFP will be executed when the MFP returns from the sleep mode. Therefore, when the MFP returns from the sleep mode in the function restriction state, the failure of the portion having an abnormality may get worse or another failure may occur in other parts if the same preparation operation as in a non-error state is executed.
For example, when a fixing motor that rotates a fixing unit of the MFP cannot rotate properly, the failure may occur in a heating member of the fixing unit if the preparation operation of the fixing unit for the return period from the sleep mode is executed repeatedly. Naturally, in a case where the failure gets worse or occurs in other parts, a user will be requested to have a longer period of downtime than that for repairing the error that has initially occurred.
Furthermore, due to the above-described situation in which the MFP shifts to the sleep mode more frequently in order to save power, there is a high risk in which the failure gets worse or occurs in other parts, and thus the downtime thereof will be longer.